In recent years, a rapid increase in obesity involved in westernization of lifestyle has become a serious problem. The obesity means a state in which excessive energy is accumulated because of excessive ingestion of calories and a decrease in calorie consumption caused by insufficient exercise or the like, and is “state in which excessive amount of fat tissues of a body (body fat) is accumulated”. It has been indicated that the obesity can be a basis of onset of so-called lifestyle-related diseases such as diabetes, hypertension and hyperlipidemia and so forth.
The obesity exhibits a state of accumulation of excessive body fat and a phenomenon of body weight increase. It is reported that, when rapid decrease of body weight is conducted to improve obesity, amounts of muscles essential for energy consumption are also decrease together with the fat, and in a case of elders, symptoms such as blood pressure disorder and injury of articulatio coxae may occur (Non-patent Document 1). Furthermore, there is a report on an exercise therapy which is expected to exert an effect of improving muscle tissues in a case where decrease of the amount of fat is conducted without reducing a body weight (Non-patent Document 2). As described above, in recent years, methods of improving obesity by inhibiting accumulation of body fat instead of merely decreasing body weight have been attracting attention.
The fat tissues are grouped into subcutaneous fat which is accumulated inside of a skin and visceral fat which is accumulated around visceral organs in an abdominal cavity, which are collectively called “body fat”. It is known that obesity is classified into groups of: subcutaneous fat type obesity involving accumulation of the subcutaneous fat; and visceral fat type obesity involving the visceral fat accumulation. The visceral fat accumulation particularly gives large effects on frequency of onset of complications such as abnormal metabolism and cardiovascular diseases and severity thereof in obesity.
Conventionally, it is known that pathosis in which an individual is suffering from a combination of a plurality of lifestyle-related diseases, that is, “multiple risk factor syndrome”, significantly increases the risks of onset of arteriosclerotic disease, and concepts that Syndrome X and metabolic syndrome is risk factors of arteriosclerosis have been proposed. Because of the proposal of those multiple risk factor syndromes, in order to achieve more comprehensive risk evaluation and to prevent the onset of arteriosclerosis, international integration of definition of metabolic syndrome and diagnostic criteria therefore were conducted (Non-patent Document 3). In the diagnostic criteria for metabolic syndrome which was proposed in Japan in April, 2005, a waist size corresponding to a visceral fat area of 100 cm2 or more is adopted as an essential item instead of a body mass index (BMI) or a body fat percentage which is generally used for indicating a level of obesity. Thus, the visceral fat accumulation has been recognized to be largely involved in the cause of the metabolic syndrome.
Exercise, diet and behavior therapies are recommended as means for decreasing body fat. However, in a case where those therapies are difficult to be carried out or continued, drug therapy or a surgery may be conducted. At present, mazindol that is an anorectic is used as a therapeutic drug for obesity, and is basically prescribed only for person suffering from high levels of obesity which show BMI of 35 or more. However, mazindol not only gives side effects such as headache and dry mouth, but also has a large number of problems in that mazindol has contraindication when severe dysfunctions are present in the kidney, liver or pancreas, and cannot be administered for a long period of time because of its dependency, and the like.
Plant sterols such as β-sitosterol, campesterol, stigmasterol have already been known to have a reducing effect on blood cholesterol by inhibiting absorption of the cholesterol, and there is disclosed a lipid metabolism-improving agent containing diglyceride and plant sterol as active ingredients (Patent Document 1). Further, there are disclosed an anti-obesity agent and a lipid metabolism-improving agent containing a cholestenone compound synthesized by using the plant sterols such as β-sitosterol and campesterol as a starting material, or 4-cholesten-3-one (Patent Documents 2 to 5) as an active ingredient.
The genus Aloe belonging to Liliaceae plant is a group of plants including Aloe vera (Aloe barbadenisis Miller), Aloe arborescens (Aloe arborescens Miller var. natalensis Berger) as a typical plant, and they are known to have various efficacies. Specifically, it is disclosed that an Aloe extract has a preventive or improving effect on obesity (Patent Document 6). In addition, there are disclosed a supplement having an effect of decreasing a body weight which contains 0.25% of Aloe vera powder (Patent Document 7) and an essential oil composition for controlling body weight which contains Aloe vera (Patent Document 8). Furthermore, it is reported that administration of a whole leaf of Aloe arborescens to a rat significantly decreased body weight depending on concentrations of Aloe arborescens (Non-patent Document 4 or 5).
[Patent Document 1] Japanese Patent Laid-open No. 2005-15425
[Patent Document 2] Japanese Patent Laid-open No. 07-165587
[Patent Document 3] Japanese Patent Laid-open No. 11-193296
[Patent Document 4] Japanese Patent Laid-open No. 2001-240544
[Patent Document 5] Japanese Patent Laid-open No. 05-170651
[Patent Document 6] Japanese Patent Laid-open No. 2000-319190
[Patent Document 7] New Zealand Patent No. 330439
[Patent Document 8] U.S. Pat. No. 6,280,751
[Non-patent Document 1] Journal of Applied Physiology, vol. 95, 2003, pp. 1728-1736
[Non-patent Document 2] Journal of Applied Physiology, vol. 99, 2005, pp. 1220-1225
[Non-patent Document 3] Adiposcience, vol. 2, 2005, pp. 11-15
[Non-patent Document 4] Igaku to Seibutsugaku, vol. 125, No. 5, pp. 189-194
[Non-patent Document 5] Journal of Medicine of Fujita Gakuen, vol. 22, No. 2, pp. 153-157